Unformatted text preview: 400 and 450 ° C (750 and 840 ° F) for 1 h. 10.D6 This problem asks if it is possible to produce an oil-quenched and tempered 4340 steel that has a minimum yield strength of 1400 MPa (203,000 psi) and a minimum ductility of 42%RA, and, if possible, to describe the tempering heat treatment. In Figure 10.26 is shown the tempering characteristics of this alloy. According to this figure, in order to achieve a minimum yield strength of 1400 MPa a tempering temperature of less that about 425 ° C is required. On the other hand, tempering must be carried out at greater than about 380 ° C for a minimum ductility of 42%RA. Therefore, an oil-quenched and tempered 4340 alloy possessing these characteristics is possible; tempering would be carried out at between 380 ° C and 425 ° C for 1 h....
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- Tensile strength, 50 days, Tempering, 315°C, minimum ductility, 380°C